Fire extinguishing method



Oct. 21, 1941. N. J. THOMPSON 4 2,259,500

FIRE EXTINGUISHING METHOD Filed Aug. 22, 1939 Patented bot. 21, 1941UNITED. STATES PATENT oFFlc-s I nxrmzzrs l na mi'rnon I l 'Norman J.Thompson, Wellesley, Mass. Application Alll'lllt 22, 1939, Sell N0.291,349

2 Claims. (01. 169-14) As is well known the most dii'ilcult flres toextinguish are those 'of flammable liquids such as acetone, lacquers orJapanning preparations, ether, gasoline, etc., particularly in the caseof exposed liquids such as pools spilled on the floor or used in openpans or vats in contradistinction to unexposed liquid such as liquidstored in a closed tank, the extinction of the exposed flres beingrendered more difllcult because of drafts of air, such as those inducedby the flre and those resulting from open windows and the like, whichincrease the rate oi combustion.

Objects of the present invention are to provide a flre extinguishingmethod ,which is simple and inexpensive to practice, which is reliableand eco-.

nomical in use, which is quick and eifective in action, which can bepracticed with permanent or portable apparatus over or near open vatswithout interfering with the normal use of the vats. which i isuniversally applicable to all flammable liquids,

which has little if any tendency to impair the quality of most flammableliquids, which permits a high proportion of salvage of unburned liquid.

' which has little if any tendency to' flood the premises, which can becontrolled either automatically by heat responsive means or manually asby hand operated valves, which does not require expensive liquids orgases, which does not require bulky fluid containers and which isgenerally superior to methods heretofore used, particularly for use inextinguishing flres in exposed places.

According to .the present invention the flre is subjected to the directaction of a spray of dis crete particles of propellant fluid such aswater or water vapor, the spray preferably diverging in the form of acone from a small nozzle opening in a substantial area,-and a gaseousflre extinguisher is entrained in'ilie spray at or near-the apex-ofthescone, While the gaseous fire extinguisher aspirator nozzle. Moreoverthe water particles 1 i help materially to extinguish the flre, not onlyby their cooling chest but also by a smothering effect as they flattenupon impingement with the surface of the flammable liquid and tend toform a fllm over the surface of the liquid. Whilethe spray of waterparticles may be formed with a jet of steam which condenses into watervapor as it emerges from the nozzle, of course the cooling effect isgreater if the spray be produced with cold water. The gaseousextinguisher which is carried to the flre by the aspirating action ofthe water spray not only tends to displace the oxygen in the region ofthe flre but its presence in and around the spray tends to prevent thespray from carrying air to the fire.

For various reasons a mixture of water particles and gaseousextinguisher is superior to a spray of either water particles alone orgaseous extinguisher alone, particularly when the water particles aresprayed directly to the flre from a.

nozzle and the gaseous extinguisher is drawn into and around a spray ofwater particles by aspirating action. Such a mixture will extinguishdifllcult flres of certain flammable liquids such as gasoline which awater spray alone will not extinguish, and less diiiicult fires of'flammable liquids are extinguished more quickly and at less expense.Even in those cases where water alone will extinguish the flre much morewater is required, thereby resulting in more water damage. When usingonly gaseous extinguisher on exposed flres it is diflicult to blanketthe flre with the gas because of drafts, and even in cases where 4tinguisher requires high pressures, and therefore expensivehigh-pressure equipment; and even preferablyconsistsin' whole or in partof carbon dioxide it may comprise any aseous fluid, such as nitrogen,boiler flue gas. or internal combusexposed flres can be extinguishedwith gas alone a relatively excessive quantity of gas is required. Thepropulsion of a stream of gaseous exthen the range of the stream is toolimited for satisfactory use except in closed buildings. In the case ofiires in open vats of flammable liquids the gas nozzles wouldhave to beplaced too close to thesurface of the liquid to permit fixed instalwiththe molecules of gaseous extinguisher; consequently the mixture of waterparticles and gaseous extinguisher. will carryconsiderable distanceswithout using excessive pressure in the lations of automatic equipmentwithout seriously interfering with the normal use ofthe vats,particularly in cleansing and lacquering establishments.

For the purpose of illustration typical embodiments of the invention areshown in the accompanying drawing in which l Y Figs. 1 and 2am side andfront elevations of one installation;

F133. 3 is a vertical central'section through a modifled aspirator;

Fig. 4 is a bottom plan view of the aspirator n shown in Fig. 3; and

Fig. 5 is a view similar to Fig. 3 showing another modification. Theparticular embodiment of the invention I shown in Figs."1 and 2 isillustrated in association with the vat It o! flammable liquid, such asa tank of cleansing fluid or a vat of lacquer for example. The apparatuscomprises a casing I! which encloses a space It serving as a mixingchamber. The casing may be supported in any suitable -way as indicatedat B. Extending downwardly through an opening in the top or the easingis a pipe il terminating in a nozzle IS within the chamber it, throughwhich the propellant fluid, such as water or steam, may be suppliedunder pressure. Extending through the rear endof the casing 15 is aconduit l8 terminating in a nozzle 2| within the chamber |6, the conduitl8 leading to a cylinder 22 of liquifled carbon dioxide or othersuitable source of gaseous extinguisher. Thelower end of the casing I5is formed as a separate funnel-shaped part forming a flaringcontinuation of the upper portion of the casing. When using water as thepropellant the nozzle 19 may be of any of the well-known types whichbreak the water stream into a divergent spray of discrete particles, andwhen using steam the nozzle may be of any well-known type which pro-.While the spray of propellant should issue from the nozzle is withconsiderable force, the gaseous extinguisher may be supplied through theoutlet 2! at a low velocity which is merely sufilcient to supply theextinguisher at the desired rate. The gaseous extinguisher is carried tothefire by the force of the propellant spray, the mixing chamher Itbeing shaped to cause a substantial amount of the gaseous extinguisherto be entrained in the spray or propellant particles. The size and ispreferably such that the divergent spray substantially fills the outletof the casing.

stiletto In the modification shown in Figs. 3 and 4 the aspirator 25comprises a conical mixing tor is very satisfactory when using-water asthe propellant.

The modified aspirator35 shown in Fig. 5 comprises a cylindrical casing86 enclosing the-upper portion of a mixing chamber 31 which alsoincludes a Venturi type outlet portion 38. The propellant is suppliedthrough conduit 39 to the nozzle lit, and the gaseous extinguisher issupplied through the conduit M to the nozzle 32. This form of theinvention is especially suited to the use of steam as the propellant. I

In each of the' illustrated modifications the depending fiaring portionof the mixing chamber serves not only toimprove the aspirating actionbut it also tends to enhance the down-draft of gaseous extinguisheraround the conical spray, thereby counteracting the usual tendency of aspray of fluid to feed the fire with air drawn-to ward the fire by thespray itself.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims.

I claim:

l. The method of extinguishing fires which comprises propelling a sprayof discrete fire ex tinguishing liquid particles from an orifice directly to the fire and with said spray aspirating to the fire a gaseousextinguisher between and around said particles.

2. The method of extinguishing fires which comprises propelling-aconical spray of discrete fire-extinguishing water particles from anorifice to the fire and in the apex portion of said conical shape of theoutlet portion 20 ot the casing it spray aspirating a gaseousextinguisher between and around the water particles, whereby the fire issubjected concomitantly to the cooling action of the water and thesmothering action of the gaseous extinguisher.

NORMAN J. THOMIPSON.

